System and method for wireless control of signs

ABSTRACT

A system includes a master controller disposed on a transit vehicle, a peripheral device disposed on the transit vehicle, a first wireless subsystem communicably coupled to the master controller, and a second wireless subsystem communicably coupled to the peripheral device. The master controller is operable to send a signal to the peripheral device via the first wireless subsystem, the signal comprising a command related to operation of the peripheral device. The peripheral device is operable to receive the signal via the second wireless subsystem and execute the command. The system utilizes a wireless protocol that specifies a unique identification for the system. The master controller and the peripheral device are each configured via the wireless protocol. The configuration includes storage of the unique identification and operability to restrict wireless communication to wireless communication with other devices so configured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims priority from, and incorporates by reference theentire disclosure of, U.S. Provisional Application No. 61/308,187 filedon Feb. 25, 2010. This Application incorporates by reference U.S. patentapplication Ser. No. 12/964,595 filed on Dec. 9, 2010.

BACKGROUND

Technical Field

The present invention relates in general to control systems forperipheral devices, and more particularly, but not by way of limitation,to systems and methods for wireless control of peripheral devicesincluding, but not limited to, electronic signs disposed relative totransit vehicles.

History of Related Art

Signage is a critical aspect of communication in our organized society.Signage used in the public-transit industry is a well known example ofthis critical use. A plurality of signs may often be positioned inand/or around a bus, train, or other mode of transit to displayinformation to passengers, potential passengers, and/or other observers.For example, busses often display route information on signs disposed onthe outside of busses so the sign information can easily be observed.Rider decisions are often based on such signs. The information mayinclude the name of the route that particular bus is servicing. In thatway, potential passengers waiting at a bus stop will know which bus toboard.

In early days of mass transportation, bus operators often used a placarddisplaying a route number which was placed in a window of the bus.Eventually, such placards were replaced by electronic signs capable ofdisplaying a selected route number thereon. To power the electronicsigns on the bus, a power cord had to be run to each electronic sign. Aroute number to be displayed also had to be input into the electronicsigns. The route number could either be manually input into eachelectronic sign or a communication link had to be hardwired from acontrol box to each sign to be controlled.

More advanced hardwired systems have utilized master and slave moduleconfigurations. For example, various prior art systems include severalperipheral (slave) modules and a master controller. The master may behardwired to the slave modules with a RS-485 bus. The master may controlthe slave peripherals utilizing a serial protocol such as wired RS-485communications operating at 19200 Baud. The communication protocol maybe based on the Intel Hex protocol using ASCII characters.

Hardwiring a control box to a plurality of electronic signs presents anumber of drawbacks. For example, the wires for communicating with thesigns cost money to manufacture and install into the busses.Additionally, the wires for communicating with the signs add additionalweight to the busses. Additional weight increases fuel consumption,thereby increasing the cost to operate the busses. Another issue is thedifficulty in maintaining and/or replacing the wires.

SUMMARY OF THE INVENTION

In one embodiment, a system includes a master controller disposed on atransit vehicle, a peripheral device disposed on the transit vehicle, afirst wireless subsystem communicably coupled to the master controller,and a second wireless subsystem communicably coupled to the peripheraldevice. The master controller is operable to send a signal to theperipheral device via the first wireless subsystem, the signalcomprising a command related to operation of the peripheral device. Theperipheral device is operable to receive the signal via the secondwireless subsystem and execute the command. The system utilizes awireless protocol that specifies a unique identification for the system.The master controller and the peripheral device are each configured viathe wireless protocol. The configuration includes storage of the uniqueidentification and operability to restrict wireless communication towireless communication with other devices so configured.

In one embodiment, a method includes providing a wireless-communicationsystem on a transit vehicle. The wireless-communication system includesa master controller disposed on the transit vehicle, a peripheral devicedisposed on the transit vehicle, a first wireless subsystem communicablycoupled to the master controller, and a second wireless subsystemcommunicably coupled to the peripheral device. The method furtherincludes configuring the master controller and the peripheral device viaa wireless protocol for the wireless-communication system. Theconfiguring includes storing a unique identification for thewireless-communication system and restricting wireless communication towireless communication to other devices so configured. The methodadditionally includes sending a signal by the master controller via thefirst wireless subsystem, the signal comprising a command related tooperation of the peripheral device. Further, the method includesreceiving the signal at the peripheral device via the second wirelesssubsystem and executing the command at the peripheral device.

The above summary of the invention is not intended to represent eachembodiment or every aspect of the present invention. It should beunderstood that the various embodiments disclosed herein can be combinedor modified without changing the spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and apparatus of the presentinvention may be obtained by reference to the following DetailedDescription when taken in conjunction with the accompanying Drawingswherein:

FIG. 1 is a perspective view of a bus utilizing an embodiment of awireless system;

FIG. 2A is a block diagram of an embodiment of a wireless system;

FIG. 2B illustrates a process for building a pseudo-random hoppingsequence;

FIG. 3 is a table showing an exemplary embodiment of a wireless packetformat;

FIG. 4 illustrates a process of sending data to/from a control panel anda slave peripheral device;

FIG. 5 illustrates an exemplary process for configuring a slaveperipheral device;

FIG. 6 illustrates an embodiment of a computer; and

FIG. 7 is a diagram illustrating an embodiment of a cabin-lightingsystem.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In various embodiments, wireless control of peripheral devices on atransit vehicle may be facilitated. For purposes of this patentapplication, a “peripheral device” may be considered a device that isattached or installed, for example, on a transit vehicle and expands thetransit vehicle's capabilities. Peripheral devices may include, forexample, lights, signs, audio and/or video components, climate-controlsystems, and the like. A “transit vehicle,” as used herein, includes,but is not limited to, land, water, or air-based vessels or vehiclesincluding, but not limited to, water vessels, aircraft, and land-basedvehicles (e.g., busses or trains).

FIG. 1 illustrates a bus 100. Although the bus 100 is depicted in FIG.1, it is contemplated that other types of transit vehicles may also beused such as, for example, a train or an airplane. A sign 102 is shownon the bus 100. The sign 102 typically displays information pertainingto a route, such as, for example, a route number or route name. However,other information could be displayed by the sign 102. As one of ordinaryskill in the art will appreciate, a transit vehicle such as, forexample, the bus 100, may have a plurality of signs similar to the sign102 thereon. For example, a transit vehicle may have a sign similar tothe sign 102 on each of a front, middle, and left and right sides of thetransit vehicle. By way of further example, the transit vehicle may haveone or more signs similar to the sign 102 inside the transit vehicle.Typically, information to be displayed by the sign 102 is programmedremotely by a wired master control, or manually on a control panellocated on the sign 102. In various embodiments, information may bedisplayed by the sign 102 in a wireless configuration.

FIG. 2A illustrates a wireless-communication system 200. Thewireless-communication system 200 is shown in an exemplary embodiment. Amaster controller (device) 202 is connected to a wireless subsystem 204.A wireless subsystem 206, which is in communication with the wirelesssubsystem 204, is connected to a slave peripheral device 208. Thewireless subsystem 206 may be connected to the slave peripheral device208 via, for example, a wired connection. In various embodiments, thewireless subsystem 206 may be physically part of the slave peripheraldevice 208 so as not to require a separate wired connection. Similarly,the wireless subsystem 204 may be connected to the master device 202 viaa wired connection. In various embodiments, the wireless subsystem 204may be physically part of the master device 202 so as not to require aseparate wired connection.

For simplicity of illustration, only the slave peripheral device 208 isshown. However, in a typical embodiment, the slave peripheral device 208may represent a plurality of slave peripheral devices, each of which hasa wireless subsystem similar to the wireless subsystem 206. For example,in various embodiments, the slave peripheral device 208 may represent aplurality of electronic signs such as, for example, the sign 102 ofFIG. 1. By way of further example, the slave peripheral device 208 mayrepresent a plurality of peripheral devices selected from anycombination of lights, electronic signs, audio and/or video components,climate-control components, and the like. In a typical embodiment, themaster device 202 may include a control panel. In other embodiments, themaster device 202 may communicate and receive data from aphysically-separate control panel that is communicably coupled to themaster device 202.

In operation, the master device 202 sends a signal to the wirelesssubsystem 204. The signal may include one or more commands such as, forexample, commands to adjust operation of the slave peripheral device 208and/or a plurality of slave peripheral devices that may be present inthe system 200. By way of example, the signal may include a command toadjust a brightness of a light, adjust a temperature of aclimate-control component, or adjust what is displayed by an electronicsign or an appearance of the electronic sign. In a typical embodiment,the wireless subsystem 204 converts the signal into data packets forwireless transmission. An exemplary data packet format will be describedwith respect to FIG. 3. The data packets may be compressed in order tominimize an amount of data transmitted. Compression of the data packetscan be accomplished in a number of ways including, for example, usingbinary values instead of ASCII characters and by reducing or eliminatingcertain fields. The wireless subsystem 206 receives the data packets andthen processes the data packets and sends the signal to the slaveperipheral device 208. The signal may be processed, for example, by aprocessor in the peripheral device that causes the commands to beexecuted by appropriate components of the slave peripheral device 208.In a typical embodiment, the wireless subsystem 204 and the wirelesssubsystem 206 are operable to transmit data at a rate between 60 and 200kbps in order to minimize delay spread multi-path effects. Additionally,in a typical embodiment, the wireless-communication system 200 transmitssignals at between 1 and 100 milliwatts of radio frequency (RF) power.

In various embodiments, the master device 202 may be directly wired tothe slave peripheral device 208 as shown, for example, to program theslave peripheral device 208 with a unique identification (ID) code forthe master device 202. In various other embodiments, the master device202 may be directly wired to the slave peripheral device 208 as shown tosupport, for example, backwards compatibility with communicationprotocols, such as, for example, RS-485 communications based on theIntel Hex protocol using ASCII characters and operating at 19200 Baud.

In various embodiments, the wireless-communication system 200 may use afrequency hopping spread spectrum under Federal CommunicationsCommission (FCC) 15.247. A frequency hopping spread spectrum system cantransmit data in discrete packets using a different frequency for eachsuccessive packet. Alternatively several packets can be sent on the samefrequency as long as no frequency is used for longer than 400 msec.Transmit frequencies can be chosen from a pseudo-random list.Alternatively transmit frequencies can be pre-defined. In variousembodiments, the wireless-communication system 200 can use directsequence spread spectrum under FCC 15.247. The wireless-communicationsystem 200 can use several different channels each utilizing directsequence spread spectrum. In various embodiments, thewireless-communication system 200 can use a combination of directsequence and frequency hopping spread spectrum. In various embodiments,the wireless-communication system 200 can use one or more fixedfrequency RF channels. In various embodiments, thewireless-communication system 200 can use a combination of fixedfrequency and/or frequency hopping and/or direct sequence spreadspectrum.

In various embodiments, the wireless-communication system 200 mayutilize a wireless protocol that includes, for example, methods to sendand receive data packets, mitigate errors, choose transmit frequencies,and synchronize operation between the master device 202 and slaveperipheral devices such as, for example, the slave peripheral device208. Due to the possibility of two or more transit vehicles being closeenough to each other to cause interference between wireless systems,each wireless-communication system such as, for example, thewireless-communication system 200, can have a unique frequency hoppingsequence. If direct sequence spread spectrum is used, eachwireless-communication system such as, for example, thewireless-communication system 200, may have a unique spreading code. Iffixed frequencies are used, each wireless-communication system such as,for example, the wireless-communication system 200, can use a frequencychosen from a larger group of frequencies.

FIG. 2B illustrates a process 250 for building a pseudo-random hoppingsequence (i.e., sequence list) according to an exemplary wirelessprotocol. In a typical embodiment, the process 250 utilizes a unique IDassigned, for example, to a wireless-communication system for a transitvehicle. The unique ID may be, for example, a random number, asequential number, a number related to a vehicle such as, for example, abus number or vehicle identification number (VIN), a number related tothe product such as, for example, a serial number, a number chosen by acustomer, and the like.

For purposes of illustration, the sequence list generated in the process250 includes twenty-five channels. The process 250 begins at step 252.At step 252, a first channel in the sequence list is set. The firstchannel is typically fixed at a first available channel in, for example,the 902-928 Mhz band. As described in more detail below, in a typicalembodiment, the other twenty-four channels may be chosen via, forexample, a random-number generator. After step 252, the process 250proceeds to step 254.

At step 254, the random-number generator may use the unique ID as a seedto generate a random number. After step 254, the process 250 proceeds tostep 256. At step 256, the process 250 may take the random number moduloC to produce a channel candidate, where C is a number of availablechannels in the 902-928 Mhz band. After step 256, the process 250proceeds to step 258. At step 258, it is determined whether the channelcandidate is already in the sequence list. If the channel candidate isalready in the sequence list, the process 250 returns to step 254 forgeneration of a new random number. Otherwise, if the channel candidateis not already in the sequence list, the process 250 proceeds to step260.

At step 260, the channel candidate is placed in the sequence list. Afterstep 260, the process 250 proceeds to step 262. At step 262, it isdetermined whether the sequence list contains twenty-five entries. Ifthe sequences list does not contain twenty-five entries, the process 250returns to step 254 for generation of a new random number. Otherwise, ifthe sequences list contains twenty-five entries, the process 250proceeds to step 264. At step 264, the process 250 ends.

In a typical embodiment, a master device such as, for example, themaster device 202 of FIG. 2A, and each slave peripheral device such as,for example, the slave peripheral device 208 of FIG. 2A, execute a samealgorithm. In various embodiments, the algorithm may be similar to theprocess 250. Using the same unique ID and the same algorithm, eachdevice will have an identical sequence list. One of ordinary skill inthe art will appreciate that systems with different unique IDs will havedifferent pseudo-random sequences. The sequence list described above isoftentimes called a hop table. The hop table may be used as an indexinto a table of C equally spaced frequencies in the 902-928 Mhz band. Bysequentially indexing through the hop table the system will “hop” in apseudo-random fashion. The number of available channels in the 902-928Mhz band depends on the data rate and modulation used. The FCC defineschannels as being separated by at least the 20 dB bandwidth of achannel. In various embodiments, there may be, for example, between 50and 200 available channels.

FIG. 3 illustrates a wireless packet format 300 that may be utilizedaccording to an exemplary wireless protocol. In order to send datapackets wirelessly to/from master and slave peripherals, the datapackets can be encapsulated in a wireless packet format such as, forexample, the wireless packet format 300. As illustrated in FIG. 3 anddescribed in Table 1 below, the wireless packet can contain one or moreof the following:

TABLE 1 FIELD DESCRIPTION Preamble A bit sequence of 1's and 0's used tosynchronize the receiver's bit recovery clock. Header A bit sequenceused to identify the first byte boundary. ID A bit field that is commonto all devices within a single transit vehicle network and is unique toeach transit vehicle network. CMD A bit field that defines a type orpurpose of the packet. Length A bit field that defines a length of thepacket. The length field refers to the length of the data field. Seq # Abit field that is incremented every time a new packet is sent. If thepacket is a resend of a previous packet the sequence number is notincremented. This allows the receiver to distinguish between new packetsand retries Data Payload. CRC A cyclic redundancy check, check sum orother bit sequence used to detect errors in the packetOther wireless packet formats are possible using different fields and/ora different number of bits for each field.

FIG. 4 illustrates a process 400 of sending data to/from a master deviceand a slave peripheral device according to an exemplary wirelessprotocol. In order to synchronize transmitters and receivers in afrequency hopping system, it is generally advisable to keep track oftime as well as the hopping sequence. To accomplish this, the exemplarywireless protocol can utilize time slots. A time slot is a predeterminedfixed length of time during which a given frequency will be used. Oncethe slave peripheral device is synchronized to the time slot and hoppingfrequency, the receiver can determine which frequency to use at anygiven time in the future without the requirement of receiving everypacket. The time slot size can be based on the maximum packet transfertime. Alternatively the time slot can be a multiple of the packettransfer time.

In a typical embodiment, a master device such as, for example, themaster device 202 of FIG. 2A, defines time slots by beginningtransmission at the start of a time slot. Slave peripheral devices suchas, for example, the slave peripheral device 208 of FIG. 2A, receive atransmission from the master device and keep track of the time to thenext time slot. At power up, the slave peripheral devices synchronize tothe time slot and hopping sequence. To accomplish this, the masterdevice typically sends synchronize messages continuously for a minimumnumber of time slots before beginning to send data packets. The slaveperipheral devices then tune to a pre-determined channel in the hopsequence and listen for a valid transmission from the master device.

A valid transmission is any transmission that contains no errors andmatches the unique ID. Once the slave peripheral devices receive a validpacket, the slave peripheral devices start a timer to measure the timeto the start of the next time slot. Synchronization may be maintained byresetting the timer each time the slave peripheral devices receive avalid packet. If for any reason the slave peripheral devices losesynchronization, the slave peripheral devices may again tune to thepredetermined channel and listen for the master device 202. The numberof time slots that can be missed and still remain synchronized dependson the accuracy of the clocks in the master device 202 and the slaveperipheral devices, the time slot length, and the guard time. With a 1msec guard time and a clock accuracy of +/−50 ppm, a slave peripheraldevice can miss 1250 packets before losing synchronization.

After synchronization between the master device and the slave peripheraldevice, the master device can send data packets to the slave peripheraldevices when, for example, the master device receives data from thecontrol panel (i.e., ODK). When the slave peripheral device receives thedata packet from the master device, the slave peripheral device checksthe address and CRC, and returns an acknowledgement if the data packetwas error free and destined for this slave peripheral device. The slaveperipheral device then decompresses the packet and causes execution ofcommands contained therein by functional components of the slaveperipheral device (i.e., sign). After the master device has sent thedata packet, the master device will poll the slave peripheral device forreturn data. In response to a poll command, the slave peripheral devicecompresses the data the slave peripheral device received, and sends aresponse packet to the master device.

FIG. 5 illustrates an exemplary process 500 for configuring a slaveperipheral device such as, for example, the slave peripheral device 208of FIG. 2A. As described above, a unique ID may be assigned to eachwireless-communication system such as, for example, the wirelesscommunication system 200 of FIG. 2A. Each wireless-communication systemgenerally comprises one master device and at least one slave peripheraldevice. In a typical embodiment, the unique ID ensures that only devicesintended to be a part of the system are allowed to communicate and otherdevices within range but belonging to a different system cannot exchangedata by mistake. In a typical embodiment, the unique ID is uniquelyconfigured in each device when the system is first installed. If adevice within a system is ever replaced, a new device can bereprogrammed or resynchronized with the unique ID. In variousembodiments, the master device may contain a unique ID when shipped froma factory. Therefore, each slave peripheral device that is in a samewireless-communication system as the master device may be configuredaccording to the unique ID.

At step 502, an initial unique ID of zero may be assigned to the slaveperipheral devices. In various embodiments, any slave peripheral devicesused by the system may be shipped with the unique ID of zero. After step502, the process 500 proceeds to step 504. At step 504, afterinstallation of the slave peripheral devices, or in the event ofreplacement due to upgrade or failure, a configuration command may beentered into the master device and system power may be cycled. Afterstep 504, the process 500 proceeds to step 506. At step 506, when themaster device powers up the first time, the master device transmits aprogram message, instead of the sync message described with respect toFIG. 4, one-hundred times before resuming normal operation. The programmessage typically contains the master device's unique ID. After step506, the process 500 proceeds to step 508.

At step 508, when the slave peripheral devices power up, the slaveperipheral devices check the unique ID stored in nonvolatile memory. Ifthe unique ID is not zero, the slave peripheral devices use the storedunique ID and only accept messages from the master device containing theunique ID and the process 500 proceeds to step 512. If the unique ID isdetermined to be zero at step 508, the process 500 proceeds to step 510.At step 510, the slave peripheral devices listen for the programmessage, for example, on channel one for up to one second. When theslave peripheral devices receive the program message, the slaveperipheral devices store the unique ID contained in the program messagein nonvolatile memory. After step 510, the process 500 proceeds to step512. At step 512, the process 500 ends.

In addition to being programmed with a unique ID at the factory, themaster device may have the ability to accept a unique ID through akeypad on the master device. Likewise, slave peripheral devices have aswitch on the internal circuit card that allows a technician to set theunique ID to zero. A light-emitting diode (LED) indicator indicates theunique ID is set to zero. In addition, peripheral devices may have aninternal serial connection (e.g., RS-232 or Universal Serial Bus (USB))that will allow programming of the unique ID directly. The serialconnection and the internal switch is typically placed in such a waythat a cover must be removed in order to gain access to these functions.

In various embodiments, various other methods may also be utilized toconfigure master devices and/or slave peripheral devices. For example, ahandheld device can be developed to attach to each slave and/or masterdevice and to program each with the unique ID code. Alternatively ahandheld device can be developed to wirelessly communicate with eachmaster device and/or slave peripheral device and program each unit withthe unique ID code. In various embodiments, the master device and/orslave peripheral devices may have a push button. For example, when thebuttons on the master device and the slave peripheral devices arepushed, the master device may transmit the unique ID code and each slaveperipheral device may receive and store the unique ID code.

Additionally, in various embodiments, a wiring cable can be temporarilyconnected between the master device and slave peripheral devices. Usingthis cable the master device may program each slave peripheral devicewith the master device's unique ID code. A module or circuit boardcontaining the unique ID code can also be inserted into each masterdevice and/or slave peripheral device. Each master device and/or slaveperipheral device can have a slot or opening or removable cover tofacilitate the insertion of the module or circuit board. Each masterdevice and/or slave peripheral device can have a magnetic card reader. Amagnetic card with the unique ID code can then be swiped on each deviceto program the unique ID code into each device. Each master deviceand/or slave peripheral device can have a RFID reader. A RFID card withthe unique ID code can then be presented or attached to each device toprogram the unique ID code into each device. In various embodiments, themaster device and/or slave peripheral devices can be configured with aunique ID code at the factory and sent together to the customer.

FIG. 6 illustrates a computer 600 that may be included within a slaveperipheral device such as, for example, the slave peripheral device 208of FIG. 2A and a master device such as, for example, the master device202 of FIG. 2A. The computer 600 includes memory 616, a centralprocessing unit (CPU) 618, a display 620, an input device 622 and acommunication unit 624. Particular embodiments of a master device or aslave peripheral device may omit various components such as, forexample, a display 620.

FIG. 7 shows a front panel of an exemplary embodiment of a control panel750 that may be communicably coupled to a master device such as, forexample, the master device 202 of FIG. 2A. In a typical embodiment, thecontrol panel 750 allows a user to adjust the intensity of one or morelights in an interior of a cabin of a transit vehicle. The control panel750 includes a display 755 and a plurality of buttons 761-768. A pair ofbuttons 761, 762 are used to scroll up and down a menu structure that isdisplayed on the display 755 and an ENTER button 763 is used to entermenu selections. A set of buttons 765-768 are used to control thegeneration of white light. In various embodiments, peripheral devices(e.g., lighting components) may be controlled from the control panel750.

Although various embodiments of the method and apparatus of the presentinvention have been illustrated in the accompanying Drawings anddescribed in the foregoing Detailed Description, it will be understoodthat the invention is not limited to the embodiments disclosed, but iscapable of numerous rearrangements, modifications and substitutionswithout departing from the spirit of the invention as set forth herein.

What is claimed is:
 1. A method comprising: providing a plurality oftransit-vehicle peripheral devices, wherein the plurality oftransit-vehicle peripheral devices comprises an electronic sign and atleast one device selected from the group consisting of a lightcomponent, a climate-control component, an audio component and a videocomponent; for each transit-vehicle peripheral device of the pluralityof transit-vehicle peripheral devices: on power up, checking, by thetransit-vehicle peripheral device, a transit-vehicle peripheral deviceprogrammable identifier stored in non-volatile memory thereof; whereinthe transit-vehicle peripheral device programmable identifier is storedas a single value such that: a specific initial value indicates that noparticular transit-vehicle master controller has been assigned to thetransit-vehicle peripheral device; and any value other than the specificinitial value identifies a particular transit-vehicle master controllerof a particular wireless transit-vehicle network that has been assignedto the transit-vehicle peripheral device; responsive to thetransit-vehicle peripheral device programmable identifier having thespecific initial value: the transit-vehicle peripheral device listeningon a predetermined channel for a message that includes a new value forthe transit-vehicle peripheral device programmable identifier;responsive to the listening, the transit-vehicle peripheral devicewirelessly receiving, from a transit-vehicle master controller of awireless transit-vehicle network, a wireless transit-vehicle networkcommon code that is common to all transit-vehicle peripheral deviceswithin the wireless transit-vehicle network; and the transit-vehicleperipheral device storing the wireless transit-vehicle network commoncode in the non-volatile memory thereof as the transit-vehicleperipheral device programmable identifier, wherein the wirelesstransit-vehicle network common code replaces the specific initial valueand is indicative of the transit-vehicle peripheral device having thetransit-vehicle master controller of the wireless transit-vehiclenetwork assigned thereto; the transit-vehicle peripheral devicesynchronizing to a time slot and hopping sequence of the transit-vehiclemaster controller of the wireless transit-vehicle network; thetransit-vehicle peripheral device wirelessly receiving a command packet;the transit-vehicle peripheral device determining whether the commandpacket includes the transit-vehicle peripheral device programmableidentifier; responsive to a determination that the command packetincludes the transit-vehicle peripheral device programmable identifier:the transit-vehicle peripheral device wirelessly acknowledging thecommand packet; and the transit-vehicle peripheral device adjustingoperation of the transit-vehicle peripheral device as indicated in thecommand packet; and responsive to a determination that the commandpacket does not include the transit-vehicle peripheral deviceprogrammable identifier, the transit-vehicle peripheral device notaccepting the command packet, thereby disallowing communication withtransit-vehicle master controllers of other wireless transit-vehiclenetworks.
 2. The method of claim 1, wherein at least some devices withinthe wireless transit-vehicle network transmit data at a rate between 60and 200 kbps so as to minimize delay spread multi-path effects.
 3. Themethod of claim 1, wherein at least some devices within the wirelesstransit-vehicle network transmit signals at between 1and 100 milliwattsof radio frequency power.
 4. The method of claim 1, wherein the wirelesstransit-vehicle network uses a combination of frequency hopping and atleast one of fixed frequency and direct sequence spread spectrum.
 5. Themethod of claim 1, wherein the specific initial value is zero.
 6. Themethod of claim 1, wherein each command, from the transit-vehicle mastercontroller of the wireless transit-vehicle network, to the plurality oftransit-vehicle peripheral devices, is contained in a packet thatincludes the wireless transit-vehicle network common code.
 7. The methodof claim 1, wherein the wireless transit-vehicle network common code isfactory-established.
 8. The method of claim 1, wherein: the plurality oftransit-vehicle peripheral devices comprises the light component, andthe climate-control component; and the command packet instructs theelectronic sign to adjust what is displayed thereby.
 9. The method ofclaim 1, wherein the transit-vehicle peripheral devices each comprise aninternal serial connection so as to receive the transit-vehicleperipheral device programmable identifier.
 10. A system comprising: atransit-vehicle master controller of a wireless transit-vehicle network,wherein the transit-vehicle master controller comprises a processor andnon-volatile memory, wherein the transit-vehicle master controller isdisposed on a transit vehicle; and a plurality of transit-vehicleperipheral devices disposed on the transit vehicle, the plurality oftransit-vehicle peripheral devices each comprising an electronic sign, aprocessor and non-volatile memory, wherein each transit-vehicleperipheral device of the plurality of transit-vehicle peripheral devicesis operable to implement a method comprising: on power up, checking, bythe transit-vehicle peripheral device, a transit-vehicle peripheraldevice programmable identifier stored in the non-volatile memorythereof; wherein the transit-vehicle peripheral device programmableidentifier is stored as a single value such that: a specific initialvalue indicates that no particular transit-vehicle master controller hasbeen assigned to the transit-vehicle peripheral device; and any valueother than the specific initial value identifies a particulartransit-vehicle master controller of a particular wirelesstransit-vehicle network that has been assigned to the transit-vehicleperipheral device; responsive to the transit-vehicle peripheral deviceprogrammable identifier having the specific initial value: thetransit-vehicle peripheral device listening on a predetermined channelfor a message that includes a new value for the transit-vehicleperipheral device programmable identifier; responsive to the listening,the transit-vehicle peripheral device wirelessly receiving, from thetransit-vehicle master controller of the wireless-transit-vehiclenetwork, a wireless transit-vehicle network common code that is commonto all transit-vehicle peripheral devices within the wirelesstransit-vehicle network; and the transit-vehicle peripheral devicestoring the wireless transit-vehicle network common code in thenon-volatile memory thereof as the transit-vehicle peripheral deviceprogrammable identifier, wherein the wireless transit-vehicle networkcommon code replaces the specific initial value and is indicative of thetransit-vehicle peripheral device having the transit-vehicle mastercontroller of the wireless transit-vehicle network assigned thereto; thetransit-vehicle peripheral device synchronizing to a time slot andhopping sequence of the transit-vehicle master controller of thewireless transit-vehicle network; the transit-vehicle peripheral devicewirelessly receiving a command packet; the transit-vehicle peripheraldevice determining whether the command packet includes thetransit-vehicle peripheral device programmable identifier; responsive toa determination that the command packet includes the transit-vehicleperipheral device programmable identifier: the transit-vehicleperipheral device wirelessly acknowledging the command packet; and thetransit-vehicle peripheral device adjusting operation of thetransit-vehicle peripheral device as indicated in the command packet;and responsive to a determination that the command packet does notinclude the transit-vehicle peripheral device programmable identifier,the transit-vehicle peripheral device not accepting the command packet,thereby disallowing communication with transit-vehicle mastercontrollers of other wireless transit-vehicle network systems.
 11. Thesystem of claim 10, wherein the specific initial value is zero.
 12. Thesystem of claim 10, wherein each command, from the transit-vehiclemaster controller of the wireless transit-vehicle network, to theplurality of transit-vehicle peripheral devices, is contained in apacket that includes the wireless transit-vehicle network common code.13. The system of claim 10, wherein the transit-vehicle network commoncode is factory-established.
 14. A computer-program product comprising anon-transitory computer-usable medium having computer-readable programcode embodied therein, the computer-readable program code adapted to beexecuted to implement a method comprising, for each transit-vehicleperipheral device of a plurality of transit-vehicle peripheral deviceswherein the transit-vehicle peripheral device includes an electronicsign: on power up, checking, by a transit-vehicle peripheral device, atransit-vehicle peripheral device programmable identifier stored innon-volatile memory thereof; wherein the transit-vehicle peripheraldevice programmable identifier is stored as a single value such that: aspecific initial value indicates that no particular transit-vehiclemaster controller has been assigned to the transit-vehicle peripheraldevice; and any value other than the specific initial value identifies aparticular transit-vehicle master controller of a particular wirelesstransit-vehicle network that has been assigned to the transit-vehicleperipheral device; responsive to the transit-vehicle peripheral deviceprogrammable identifier having the specific initial value: thetransit-vehicle peripheral device listening on a predetermined channelfor a message that includes a new value for the transit-vehicleperipheral device programmable identifier; responsive to the listening,the transit-vehicle peripheral device wirelessly receiving, from atransit-vehicle master controller of a wireless transit-vehicle network,a wireless transit-vehicle network common code that is common to alltransit-vehicle peripheral devices within the wireless transit-vehiclenetwork; and the transit-vehicle peripheral device storing the wirelesstransit-vehicle network common code in the non-volatile memory thereofas the transit-vehicle peripheral device programmable identifier,wherein the wireless transit-vehicle network common code replaces thespecific initial value and is indicative of the transit-vehicleperipheral device having the transit-vehicle master controller of thewireless transit-vehicle network assigned thereto; the transit-vehicleperipheral device synchronizing to a time slot and hopping sequence ofthe transit-vehicle master controller of the wireless transit-vehiclenetwork; the transit-vehicle peripheral device wirelessly receiving acommand packet; the transit-vehicle peripheral device determiningwhether the command packet includes the transit-vehicle peripheraldevice programmable identifier; responsive to a determination that thecommand packet includes the transit-vehicle peripheral deviceprogrammable identifier: the transit-vehicle peripheral devicewirelessly acknowledging the command packet; and the transit-vehicleperipheral device adjusting operation of the transit-vehicle peripheraldevice as indicated in the command packet; and responsive to adetermination that the command packet does not include thetransit-vehicle peripheral device programmable identifier, thetransit-vehicle peripheral device not accepting the command packet,thereby disallowing communication with transit-vehicle mastercontrollers of other wireless transit-vehicle network systems.
 15. Thecomputer-program product of claim 14, wherein the wirelesstransit-vehicle network transmits signals via at least one of fixedfrequency, frequency hopping and direct sequence spread spectrum. 16.The computer-program product of claim 14, wherein the wirelesstransit-vehicle network transmits data between 60 and 200 kbps so as tominimize delay spread multi-path effects.
 17. The computer-programproduct of claim 14, wherein the specific initial value is zero.
 18. Thecomputer-program product of claim 14, wherein each command, from thetransit-vehicle master controller of the wireless transit-vehiclenetwork, to the plurality of transit-vehicle peripheral devices, iscontained in a packet that includes the wireless transit-vehicle networkcommon code.
 19. The computer-program product of claim 14, wherein thewireless transit-vehicle network common code is factory-established. 20.The computer-program product of claim 14, wherein the wirelesstransit-vehicle network transmits signals between 1 and 100 milliwattsof radio frequency power.